A report to the New South Wales Department of Environment and Climate Change on the consultancy: ‘Kangaroo Monitoring: Hunter and Central Tablelands Commercial Harvest Zones Design and Analysis of Helicopter Survey’.

S. C. Cairns1, G. W. Lollback1 and D. Bearup2 April, 2009    1Zoology, School of Environmental & Rural Sciences, University of New England, Armidale, NSW, 2351 2New South Wales National Parks and Wildlife Service, P.O. Box 4189, Forster, NSW, 2428

Contact

Dr Stuart Cairns Zoology, School of Environmental & Rural Sciences, University of New England, Armidale, New South Wales, 2351

Telephone: (02) 67732170 (W)

(02) 67727638 (AH)

0427 454344 (M)

Fax: (02) 67733814

email: scairns@.une.edu.au

Summary

1. Helicopter surveys for kangaroos were conducted using line transect sampling in three

proposed new kangaroo management zones: the Hunter-Mudgee zone, the Central Tablelands

zone and the SE NSW (Young) zone. The population estimates derived from these surveys

were intended to be used to set quotas for a commercial harvest of eastern grey kangaroos

(Macropus giganteus) from within these zones. The first two of these proposed zones were

intended to be managed separately, the third was to be incorporated into the existing South

East NSW kangaroo management zone.

2. In conducting these surveys, each proposed zone was subdivided into three strata of

increasing kangaroo density in order to facilitate the design process. The two strata identified

as possibly supporting the highest numbers of kangaroos were surveyed. The third stratum

was not. The surveys were designed using an automated survey design algorithm (Strindberg

et al. 2004).

3. These surveys were designed with the aim of obtaining eastern grey kangaroo population

estimates with coefficients of variation of 20%. The coefficients of variation of the population

estimates obtained for eastern grey kangaroos were in the range 18-22%.

4. Eastern grey kangaroo densities were estimated as 14.74 ± 2.64 km-2 in the proposed Hunter-

Mudgee zone, 23.18 ± 5.13 km-2 in the Central Tablelands zone and 11.22 ± 2.12 km-2 in the

SE NSW (Young) zone. These densities correspond to population estimates of

433,030 ± 77,533 kangaroos in the proposed Hunter-Mudgee zone and 535,600 ± 118,607

kangaroos in the Central Tablelands zone.

 

2

1. Introduction

Core to all the kangaroo management programs in operation throughout mainland Australia is

the management for commercial harvesting of all or some of the four large species of

kangaroo that are variously widespread and abundant throughout much of the continent

(Pople & Grigg 1998). In New South Wales (NSW), all four of these species, the red

kangaroo (Macropus rufus), the eastern grey kangaroo (M. giganteus), the western grey

kangaroo (M. fuliginosus) and the common wallaroo or euro (M. robustus) are harvested from

at least some of the 12 current kangaroo management zones (Anon. 2006).

It is a legislative requirement that any commercial harvesting of kangaroos be

conducted on a sustainable basis (Pople & Grigg 1998). In order to set harvest quotas with

the intention of ensuring sustainability, it is necessary to obtain reasonably accurate estimates

of the sizes of the kangaroo populations proposed to be harvested. Eight of the kangaroo

management zones in NSW are on the western plains of the state. Estimates of the

kangaroo populations within these zones are obtained from broad-scale aerial surveys

conducted annually using fixed-wing aircraft and strip transect sampling (Payne 2007). The

other four kangaroo management zones are based on the Great Dividing Range and its

western slopes (see Fig. 1). Because of the general relief of the landscape of these

management zones, the kangaroo populations there cannot be monitored using fixed-wing

aircraft surveys. Hence, alternative methods of estimating kangaroo population densities

have had to be considered. Helicopter line transect sampling is used to monitor the kangaroo

populations in these zones. The suitability and effectiveness of this method has been

demonstrated by Clancy et al. (1997), Clancy (1999) and Southwell and Sheppard (2000).

Eastern grey kangaroo and the eastern subspecies of the common wallaroo

(M. r. robustus) are harvested commercially from the three kangaroo management zones in

the Northern Tablelands region of northern NSW (NSW National Parks & Wildlife Service

2001). Eastern grey kangaroos are harvested from the South East management zone (see

Fig. 1). The kangaroo populations in these management zones are monitored using

helicopter line transect surveys. These surveys are conducted on a triennial basis, a survey

frequency option considered to be safe to use to monitor kangaroo populations in mesic as

opposed to semi-arid rangeland environments (Pople 2003; Payne 2007). According to Pople

(2008), conducting kangaroo surveys on such a basis in areas defined as having a mesic

3 environment is of low risk with regard to quasiextinctions resulting from the implementation of

a particular harvesting program.

The first of helicopter line transect surveys used to monitor kangaroo populations in

NSW were conducted in the Northern Tablelands management zones in 2001 (Cairns 2003).

Subsequent surveys of the three management zones have since been conducted in 2004

(Cairns 2004a; Cairns et al. 2008) and 2007 (Cairns 2007a). The design of the second and

third of these surveys were improved over the design of the first through the use of area

stratification and the automated design capabilities of the DISTANCE analysis program

(Thomas et al. 2005). This design capability is GIS based and incorporates a range of

algorithms that can be used to design line transect surveys (Strindberg et al. 2004; Thomas et

al. 2005).

Following the conduct of the first helicopter survey of the Northern Tablelands

kangaroo management zones (Cairns 2003), a feasibility study was undertaken by Pople et

al. (2003) into conducting a similar survey in southeastern NSW as a precursor to the

establishment of a sustainable kangaroo harvesting program there. Following this feasibility

study, the initial survey of what was to become the South East NSW kangaroo management

zone was undertaken in 2003. This survey was stratified on the basis of the five Rural Lands

Protection Board (RLPB) districts that comprised the new kangaroo management zone, with

further stratification being applied to each of these districts in relation to kangaroo density

(Cairns 2004b). The basis upon which these density strata were defined was a combination

of landscape definition obtained through the use of geographical information systems (GIS),

knowledge of the ecology of eastern grey kangaroos (Scott-Kemmis 1979; Hill 1981a, b) and

broad information provided by NSW National Parks & Wildlife Service (NPWS) and RLPB

personnel on the distribution of kangaroos within the region (Pople et al. 2003). Survey effort

(km of transect) was allocated to the respective strata in proportion to the anticipated

densities of kangaroos within them; these densities being derived in relation to those reported

for the Northern Tablelands region by Cairns (2003). Following on from the conduct of the

initial survey which has led to the establishment of the new South East kangaroo

management zone, a second survey was conducted in 2006 Cairns 2007b). This second

survey was designed using the automated design capabilities of the DISTANCE analysis

program (Thomas et al. 2005).

4

With the continued successful management of the harvest in the Northern Tablelands

kangaroo management zones and the successful establishment of the South East NSW

kangaroo management zone, in response to a proposal put to it by the NSW Farmers

Association and the Rural Lands Protection Boards, NSW DECC has moved to explore the

possibility of opening two new kangaroo management zones, one based upon the Central

Tablelands and near central western slopes, and the other based upon the Hunter-Mudgee

region of NSW. To provide baseline information for deciding whether or not to proceed with

the establishment of these two new management zones, helicopter line transect surveys of

the kangaroo populations in these regions were conducted in September, 2008. Conducted

in association with these two surveys was a survey of the Young RLPB district with the

intention that it be included in an expanded South East NSW management zone. Reported

here are the designs and results of these three surveys.

2. Survey Areas

The two proposed new kangaroo management zones (KMZ) are within the non-commercial

zone between the existing Upper Hunter management zone (KMZ 14) in the north and the

South East NSW zone in the south (KMZ 16) (Fig. 1). The South East NSW zone will be

expanded by the incorporation into it of the Young RLPB district. The Young RLPB district

will be referred to hereafter as SE NSW (Young).

The proposed Hunter-Mudgee zone extends south from Liverpool Range that marks its

boundary with the Upper Hunter zone to its boundary with the Central Tablelands zone which

lies in a line immediately south of the town of Kandos. Its eastern boundary lies east of

Singleton and just west of Branxton in the Hunter Valley. Its western boundary lies southwest

of Wellington. This proposed new zone includes the Hunter, Mudgee-Merriwa and the

eastern part of the Dubbo RLPB districts (Fig. 2). It is bounded in the west by the existing

Coonabarabran kangaroo management zone (Fig. 1).

The proposed Hunter-Mudgee zone takes in parts of four biogeographic regions. In

the northeast, is a small portion of the North Coast Biogeographic Region (IBRA), while the

rest of the east of the zone is made up of part of the Hunter subregion of the Sydney Basin

Biogeographic Region (IBRA) (Sahukar et al. 2003). In the west, the zone comprises part of

the Brigalow Belt South Biogeographic Region (IBRA) in the north and part of the South

5 Western Slopes Biogeographic Region (IBRA) in the south (Sahukar et al. 2003). The

characteristic landforms of this zone extend from steep, hilly and undulating ranges to rolling

hills and wide valleys. There are no particularly prominent geodiversity features present like

those found in the Northern Tablelands management zones (Cairns, 2007a).

The proposed Central Tablelands zone extends south from its boundary with the new

Hunter-Mudgee zone to its boundary with the Young RLPB district in the north of the

expanded South East NSW zone. Its eastern boundary lies east of Bathurst, in line with

Wallerawang. Its western boundary is to the east of Parkes and Forbes. This proposed new

zone includes the Central Tablelands RLPB district, the eastern two-thirds of the Molong

RLPB district and the eastern half of the Forbes RLPB district (Fig. 2). It is bounded in the

west by the existing Griffith kangaroo management zone (Fig. 1).

 

 

Fig. 1. The 12 current kangaroo management zones administered by NSW DECC.

6

The proposed Central Tablelands zone takes in parts of two biogeographic regions. In

the east, it includes part of the South Eastern Highlands Biogeographic Region (IBRA), while

in the west, it includes part of the South Western Slopes Biogeographic Region (IBRA)

(Sahukar et al. 2003). The topography of the South Eastern Highlands Biogeographic Region

comprises the western fall of the Great Dividing Range, with relatively steep, hilly and

undulating terrain in the east giving way to hilly ranges and peaks set in wide valleys in the

west. The topography of the South Western Slopes Biogeographic Region also comprises

the western fall of the Great Dividing Range, with relatively steep, hilly and undulating terrain

in the east giving way to hilly ranges and peaks set in wide valleys in the west. Perhaps the

most important defining feature of the geodiversity of this zone is the Canobolas volcanic field

of the South Eastern Highlands Biogeographic Region (Sahukar et al. 2003).

Fig. 2. The proposed new kangaroo management zones and their constituent RLPB districts. See text for details on the proposed zone boundaries.

7

The Young RLPB district of the South East NSW zone, SE NSW (Young), is directly to

the south of the Central Tablelands and Forbes RLPB districts (Fig. 2). It is entirely within the

South Western Slopes Biogeographic Region (IBRA) (Sahukar et al. 2003).

Most of the land in these three survey areas is freehold, with some state forests,

gazetted reserves and national parks comprising small proportions of their total areas. The

principal land use practised is the grazing of domestic livestock, with the growing of grain and

oilseed crops being a prominent secondary land use. Horticulture and coal mining also

feature as significant forms of land use in the Hunter-Mudgee and Central Tablelands

management zones.

For the purpose of conducting kangaroo surveys, those parts of the two proposed

management zones and SE NSW (Young) dominated by cultivation or mining, along with

those dominated by rocky outcrops and some steep, timbered country were deemed to be

areas supporting zero to very low densities of kangaroos. The remainder was divided into

areas likely to support either medium or high densities of kangaroos. For the areas of the

three kangaroo management zones, see Table 1.

3. Survey Design

As has been the case with the most recent aerial surveys conducted in the Northern

Tablelands kangaroo management zones (Cairns 2007a) and South East NSW kangaroo

management zone (Cairns 2007b), the surveys reported on here were designed using the

automated design capabilities of DISTANCE 5.0 (Thomas et al. 2005). In order to do this,

kangaroo density strata, based essentially upon land capability attributes, were defined within

each of the proposed management zones, and survey effort determined in relation to the

precision of surveys conducted previously in other kangaroo management zones with habitat

that is broadly similar to the habitat of the three new survey areas.

3.1 Zone Stratification

GIS shape files for the three survey areas showing land capability attributes were obtained

from NSW DECC. These files contained eight categories of land capability which extend from

cultivation, through to mixed farming and grazing, through to grazing only with decreasing

levels of grazing intensity, through to steep, timbered country, through to rocky outcrops.

8 They also contained some information on state forests, reserves and gazetted national parks

which were all excluded from the survey areas. The eight categories of land capability were

merged to form the basis of the three strata to be used in the survey design process.

Categories 1 and 2, which are representative of areas dominated by cultivation

practices, were merged with category 8, which is representative of rocky outcrops, and some

of Category 7 (steep, timbered country) to form the basis of the likely low kangaroo density

stratum within each proposed zone. Categories 3 and 4, which are representative of areas of

grazing and low intensity cropping, were merged to form the basis of the designated medium

density kangaroo strata. Categories 5 and 6, which are representative of grazing land, and

some of Category 7, were merged to form the basis of the high density strata. The

boundaries of the merged strata were redigitised to create final, simpler versions of the three

density strata within each of the proposed management zones.

The breakdowns of the areas of the three kangaroo management zones into their constituent

strata are given in Table 1. In the proposed Hunter-Mudgee zone, 35% of the area formed

the high density stratum, 51% formed the medium density stratum and 14% formed the low

density stratum. The low density stratum included parts of the Goulburn River and the

Wollemi National Parks. The medium density stratum was divided for the purpose survey

design into two sub-strata of approximately equal size which were identified as Mudgee-

medium (7,646 km2) and Hunter-medium (7,406 km2). A large tract of land dominated by

open cast coal mining was excluded from the Hunter-medium sub-stratum. In the proposed

Central Tablelands zone, this breakdown was 36% high density, 62% medium density and

2% low density. In SE NSW (Young), the breakdown was 36% high density, 38% medium

density and 26% low density. For visual representation of the stratification of the zones, see

Figs. 3-5.

3.2 Survey Effort

In line transect sampling, survey effort is defined as the total length of transect surveyed.

Although ultimately constrained by cost, survey effort is generally determined in relation to

some desired level of precision (the ratio of standard error to mean). In the conduct of

surveys such as those reported upon here, setting the level precision at 20% would appear to

be realistic and cost-effective (Pople et al. 2003; Cairns et al. 2008).

9

Table 1. Areas (km2) of the three kangaroo management zones (KMZ) divided into three survey strata representing likely high, medium and low kangaroo density. The survey areas comprise the medium and high density strata.

Kangaroo management zone Stratum Hunter-Mudgee Central Tablelands SE NSW (Young)

Total area 29,379 23,102 8,884 High density 10,274 8,254 3,185 Medium density 15,052 14,378 3,353 Low density 4,053 470 2,346 Survey area 25,326 22,632 6,358

For the proposed Hunter-Mudgee and Central Tablelands zones, the respective survey

efforts were determined broadly in relation to a target level of precision of 20% for estimating

eastern grey kangaroo densities. This condition was relaxed to 30% in relation to the SE

NSW (Young) zone. The reason for this was that this zone will be surveyed again in 2009 as

part of the triennial survey of the whole of the SE NSW management zone. This being the

case, the outcome of the present survey can become the pilot survey for the 2009 survey.

To determine the effort required to attain the target levels of precision, the following

equation from Buckland et al. (2001) was used:

ˆ

ˆ2

0 02

t

L {cv (D)}L ={cv (D)}

(1)

where, L is the required survey effort for a target level of precision of ˆtcv (D) , and 0L and

cv (D)0ˆ are the survey effort and attained level of precision, respectively, from a previous or

pilot survey.

In the case of the proposed Hunter-Mudgee management zone, the most recent

survey conducted in the Upper Hunter management zone (Fig. 1: KMZ14) (Cairns 2007a)

was used as the pilot survey for determining survey effort. The precision of that survey was

combined with a survey effort that had been scaled up from the actual effort of the survey

conducted in that zone. The scaling up of the pilot survey effort was by the ratio of the areas

10 of the combined high and medium density strata of the proposed Hunter-Mudgee zone to the

combined area of those two strata in the Upper Hunter zone. In the case of the proposed

Central Tablelands management zone, this same process was followed using the most recent

survey conducted in the Armidale management zone (Fig.1: KMZ 9) (Cairns 2007a) as the

pilot survey. Similarly, for the SE NSW (Young), this process was followed using the most

recent survey conducted in the Gundagai RLPB district of the SE NSW management zone

(Fig. 1: KMZ 16) (Cairns 2007b) as the pilot survey. Selection of the particular sets of pilot

survey information was based upon the broad landscape and land use similarities between

management zones for which the required information already existed and the proposed new

management zones.

For the proposed Hunter-Mudgee zone, the pilot survey information was 0L = 330 km,

0ˆcv (D) = 19%, while for the proposed Central Tablelands zone, the pilot survey information

was 0L = 474 km, 0ˆ( )cv D = 21.0% (Cairns 2007a). For SE NSW (Young) zone, it was 0L =

334 km, 0ˆ( )cv D = 28% (Cairns 2007b). For all three surveys, ˆ

tcv (D) was set at 20%.

Once the survey efforts for the planned surveys were settled upon, they were divided

and allocated proportionally to the high density and medium density strata of each of the three

proposed zones (Table 2). No effort was allocated to the low density strata of any of the

zones. Low density strata, which comprised either areas dedicated to cropping or areas of

heavily timbered and rugged terrain, were thought to support only trace numbers of

kangaroos (Southwell et al. 1995; Cairns 2007b). Note that the survey efforts (L) given in

Table 2 are not exact as determined by Eqn. (1), but are rounded values derived from the

exact values.

3.3 Automated Survey Design

The principal aim of designing a survey is to obtain optimal estimates of abundance,

preferably with high precision and low bias (Strindberg et al. 2004). Achieving this is not

straightforward, particularly when designing a survey by hand. However, taking advantage of

GIS and using automated design algorithms such as those offered by DISTANCE 5.0

(Thomas et al. 2005) increases the likelihood that an optimal design will be achieved

(Strindberg et al. 2004).

11

DISTANCE 5.0 offers four different classes of survey design for surveys of the type to

be undertaken here: parallel random sampling, systematic random sampling, systematic

segmented trackline sampling and systematic segmented grid sampling (Thomas et al. 2005).

According to Buckland et al. (2001) and Strindberg et al. (2004), systematic designs give

smaller variation in density estimation from one realisation to the next and avoid any problems

associated with overlapping samplers (transects). Hence, a survey design incorporating

systematic segmented grid sampling with a buffer zone around the boundary of each survey

stratum was selected as the most likely design option for the present surveys. It was tested

for survey coverage against a systematic random sampling option. As well as this, the option

of maintaining the integrity of individual samplers (transects) was tested against the option of

using split samplers.

Systematic segmented grid sampling randomly superimposes a systematic set of

segmented parallel lines onto the survey region (Thomas et al. 2005). Inclusion of a buffer in

the design guards against the problem arising whereby the distribution of objects from the

transect line is not in general uniform out to the truncation distance if the transect line

intersects the stratum boundary (Strindberg et al. 2004). Inclusion of a buffer of unspecified

size (determined by the algorithm) results in what is termed minus sampling (Thomas et al.

2005). The buffers in adjacent strata do not overlap.

Surveys were designed separately for the high and medium density strata of each of the three

proposed management zones using the nominal survey efforts given in Table 2. For each

survey, a series of 99 simulations was run in relation to a 2-km square coverage grid to

assess the evenness of the coverage probability of the various survey designs selected for

comparison (Strindberg et al. 2004; Thomas et al. 2005). Following this, once it had been

confirmed that the systematic segmented grid sampling design with split samplers provided

the most even coverage of the survey area, a single realisation of that selected design was

generated for each survey stratum within each management zone.

For the Hunter-Mudgee zone, the selected survey design allocated 16 transects with

nominal lengths in the range of 5-10 km to the high density stratum, 13 transects with nominal

lengths in the range of 5-12 km to the Hunter-medium density stratum and 16 transects with

nominal lengths in the range of 6-10 km to the Mudgee-medium density stratum (Fig. 3). For

the Central Tablelands zone, the survey design allocated 21 transects with nominal lengths

12

Table 2. Survey effort (L) determined for each of the three proposed kangaroo management zones (KMZ), the proportion (%) of survey effort allocated to high and medium density strata and the translation of these proportions to actual effort (Lhigh and Lmedium). All survey effort measures are in km.

KMZ

Proportional allocation L High Medium Lhigh Lmedium

Hunter-Mudgee 390 40 60 150 240 Central Tablelands 525 55 45 290 235 SE NSW (Young) 320 60 40 180 140

in the range of 4-15 km to the high density stratum and 14 transects with nominal lengths in

the range of 9-15 km to the medium density stratum (Fig. 4). For the SE NSW (Young), the

selected survey design allocated 12 transects with nominal lengths in the range of 5-15 km to

the high density stratum and 11 transects with nominal lengths in the range of 6-15 km to the

medium density stratum (Fig. 5). The nominal total survey efforts used in the design process

along with the total survey efforts of the realised survey designs are given in Table 3.

4. Survey Methods

The aerial surveys of these three proposed management zones were conducted as helicopter

surveys during the period 8-16 September, 2008. The surveys were undertaken in

accordance with the survey designs developed above (see Section 3.3), with each proposed

management zone being considered a separate entity and subdivided into three strata based

upon likely kangaroo densities, modulated by land use capability. The high and medium

strata within each zone were surveyed. The method of line transect sampling was used. In

the original design for this survey, there was a total of 103 transects to be flown across the

three proposed management zones. All of these transects were flown in this survey.

All surveys were conducted within either the two to three-hour period following sunrise

or the two to three-hour period before sunset. David Bearup (DECC), Scott Seymour (DECC)

and Stuart Cairns (UNE) were the observers. Mike Saunders (DECC) joined the survey as a

trainee observer and, after an initial period of training, replaced one of the trained observers

as an observer on some transects flown during the later stages of the survey. The helicopter

13

Fig. 3. The proposed Hunter-Mudgee kangaroo management zone. Shown are the three survey strata; the medium kangaroo density stratum being divided two sub-strata (see legend: Medium and Hunter Medium). The open-cast coal mining area of the Hunter Medium sub-stratum was not considered as part of the survey area (white). Shown also are the population centres (towns) and the placement of the survey transects within the high and medium kangaroo density strata. Note that no survey transects were placed into the low density stratum.

14

Fig. 4. The proposed Central Tablelands kangaroo management zone. Shown are the three survey strata, the population centres (towns) and the placement of the survey transects within the high and medium kangaroo density strata. Note that no survey transects were placed into the low density stratum.

15

Fig. 5. SE NSW (Young), the Young RLPB district section of the South East NSW kangaroo management zone. Shown are the three survey strata, the population centres (towns) and the placement of the survey transects within the high and medium kangaroo density strata. Note that no survey transects were placed into the low density stratum.

16

Table 3. The survey effort allocated to the design process (Lalloc) and the actual survey effort (Lactual) resultant from the design process for the high and medium density strata of the three Northern Tablelands KMZs. All survey effort measures are in km.

KMZ

High density stratum

Medium density stratum

Lalloc Lactual Lalloc Lactual Hunter-Mudgee 150 142 240 271 Central Tablelands 290 253 235 195 SE NSW(Young) 180 155 140 139

was chartered from EPS Helicopters, Yagoona NSW. Paul Caristo was the pilot. The seating

of the observers (left- and right-hand side) was allocated randomly for each survey session.

4.1 Helicopter Line Transect Surveys

In conducting the survey, the helicopter, a Bell JetRanger, with the two rear doors removed

was flown along each transect line at a ground speed of 93 km h-1 (50 kts) and at a height of

61 m (200 ft) above the ground. Navigation was by a global positioning system (GPS)

receiver (Garmin GPSMAP 275c©). The two observers occupied the two rear seats of the

helicopter and counted the kangaroos seen on either side of the aircraft. Sightings of

kangaroos were recorded into the 0-20 m, 20-40 m, 40-70 m, 70-100 m and 100-150 m

distance classes, perpendicular to the transect line. The distance classes were delineated on

metal booms extending from either side of the helicopter.

The survey transects varied in nominal length from 4-15 km. Data in the form of the

numbers of clusters (groups of one or more) of eastern grey kangaroos, common wallaroos,

red-necked wallabies and swamp wallabies seen in the different delineated distance classes

from the helicopter were recorded into micro-cassette tape recorders. The presence of other,

non-target species was noted. Tapes were transcribed at the end of each survey session.

4.2 Data Analysis Data from the helicopter line transect surveys were analysed using DISTANCE 5.0 (Thomas

17 et al. 2005). The analysis of distance sampling data such as those collected here involves

estimation of the detection probability of clusters of animals within the covered region (the

designated survey strip), then the estimation of the density of animals within the covered

region given this detection probability and, finally, the estimation of the number of animals in

the survey region given the density of animals in the covered region (Borchers & Burnham

2004). In order to estimate the probability (Pa) that a cluster of animals within the covered

area of width w is detected, the detection function g(x) representing the probability that a

cluster at perpendicular distance x from the survey transect is detected (where 0≤x≤w and

g(0) = 1) needs to be modelled and evaluated at x = 0 (Thomas et al. 2002).

Following the recommendations of Buckland et al. (2001), six detection function

models were considered in the analysis. Each model comprised a key function that, if

required, can be adjusted by a cosine or polynomial series expansion containing one or more

parameters. The different models considered were: a Uniform key function, plus either a

Cosine or Simple Polynomial series expansion; a Half-normal key function, plus either a

Cosine or Hermite Polynomial series expansion; and a Hazard-rate key function, plus either a

Cosine or Simple Polynomial series expansion. The number of adjustment terms

incorporated into the model was determined through the sequential addition of up to five

terms (the nominal default). The model with the lowest value for a penalised log-likelihood in

the form of Akaike's Information Criterion (AIC = -2 x log-likelihood + 2[p +1]; where p is the

number of parameters in the model) was generally selected as the detection function. In

selecting the final model, however, some consideration was also given to goodness-of-fit and

the shape criterion of the detection function, with those models with an unrealistic spike at

zero distance rather than a distinct 'shoulder' near the transect line, being likely to be rejected.

Because the data were collected in fixed, broad distance categories, no manipulation

of the grouping intervals was possible in order to improve the fitting of the detection function

model. However, the procedure could be improved by giving consideration to a right-hand

truncation of the data, i.e. narrowing the survey strip width (w) from 150 m to 100 m.

The density estimates of clusters of kangaroos ( ˆsD ) were determined as:

ˆˆsa

n.f(0) nD = =2L 2wLP

(2)

18 where, n is the number of sightings, f(0) is the probability density function (the detection

function rescaled to integrate to unity) of the perpendicular density data at zero distance from

the survey transect, L is the total length of the survey transect, w is the truncation point (or

half width of the survey strip) and aP is the probability that a randomly selected object (in this

case a cluster of kangaroos) in the survey strip is detected (Buckland et al. 2001). The area

surveyed is defined by 2wL. Variance estimates for the cluster densities were calculated as:

ˆ ˆ 2 2 2s svar(D ) = D {[CV(n)] + [CV{f(0)}] } (3)

where, CV(n) is the coefficient of variation for the number of sightings across the replicate

survey lines and C{(f(0)} is the coefficient of variation of the probability density function of the

perpendicular density data at zero distance (Buckland et al. 2001). Despite the problems that

may be associated with small sample sizes, the use of cluster sightings in preference to

individual sightings ensures against overestimation of the true variance (Southwell & Weaver

1993).

Dependence of the determination of cluster size on the perpendicular distance from the

transect line was assessed by regressing the natural logarithm of the cluster size (si) on the

estimated value g(x) , the detection function (i.e. the probability that a cluster at perpendicular

distance x from the transect line will be detected) that is estimated from the fit of the selected

model to the data. If the regression is significant at a very liberal significance level of α =

0.15, then the size-biased estimate of the mean cluster size ( E(s) ) is determined as that

value when detection is certain, i.e. when g(x)= 1.0. If the regression is not significant at

α = 0.15, then the mean cluster size is determined as the sample mean of the animals in the

observed clusters (s ).

If the size of a detected cluster is independent of the distance from the transect line

(i.e. if g(x) does not depend upon s), then the estimation of the density of individuals ( D ) is

simply determined as:

ˆ ˆsD = D xs (4)

19 where, the sample mean s is taken as an unbiased estimator of the mean size (E(s)) of the n

clusters in the study area. The variance of this estimate is determined as:

ˆ ˆ 2 2 2 2svar(D) = D {[CV(n)] + [CV{f(0)}] + [CV(s)] } (5)

where, cv(s) is the coefficient of variation of s , an unbiased estimator of the mean size (E(s))

of the n clusters in the study area. If, however, the cluster size is dependent upon distance

from the transect line (i.e. g(x) is dependent upon s), then s and CV(s) are replaced by

regression estimators designated as E(s)and ˆCV(E(s)) (Buckland et al. 2001).

Data were analysed to produce density estimates for the medium density and high

density strata and density and population estimates for each of the three proposed kangaroo

management zones. Where sample sizes within strata were large enough (>40), data were

post-stratified on the basis of observer, seating position within the helicopter and side-of-

aircraft (north or south) in relation to the flight along particular transects. Where sample sizes

within strata were small (<40), data were appropriately pooled.

Post-stratification was used in analysing the eastern grey kangaroo data for the high

density strata in all three proposed management zones. It was also used in analysing the

data for the medium density strata in proposed Central Tablelands management zone.

Limited sample sizes precluded the use of post-stratification in analysing the data for the two

medium sub-strata in the proposed Hunter-Mudgee zone. This was also the case for the

medium density stratum in SE NSW (Young). Further, because the number of sightings of

eastern grey kangaroos in the medium density stratum in SE NSW (Young) fell well short of

the recommended minimum number required for analysis, these data were combined with

those from the high density stratum in order to fit a global detection function. This global

detection function was then used to determine the density of eastern grey kangaroos in the

medium density stratum. The density of eastern grey kangaroos in the high density stratum

of SE NSW (Young) was determined using only data from that stratum.

20 5. Results and Discussion

Each of the three regions surveyed was subdivided into three strata based upon land

capability and likely eastern grey kangaroo densities (see Section 3.1). Of the three strata

within each region, only the high and medium kangaroo density strata were surveyed. The

low density stratum was assumed to support zero to only trace numbers of kangaroos. The

numbers of macropod sightings on each transect and the total raw counts of each species

comprising these sightings are given in Table 4.

In the proposed Hunter-Mudgee management zone (Fig. 2), 16 transects comprising 142 km

of survey effort were flown across the high density stratum. On these transects, 402 eastern

grey kangaroos were counted along with four wallaroos, four red-necked wallabies (M.

rufogriseus) and two swamp wallabies (Wallabia bicolor). Sixteen transects comprising 143

km of survey effort were flown across the medium density stratum. On these transects, 173

eastern grey kangaroos were counted along with five wallaroos and one swamp wallaby.

Thirteen transects comprising 127 km of survey effort were flown across the Hunter-medium

density stratum. On these transects, 216 eastern grey kangaroos were counted along with 15

wallaroos, one red-necked wallaby and one swamp wallaby. In the proposed Central

Tablelands zone (Fig. 3), 21 transects comprising 253 km of survey effort were flown across

the high density stratum. On these transects, 891 eastern grey kangaroos were counted

along with 19 wallaroos, two red-necked wallabies and 19 swamp wallabies. Fourteen

transects comprising 195 km of survey effort were flown across the medium density stratum.

On these transects, 471 eastern grey kangaroos were counted along with four wallaroos, four

red-necked wallabies and 19 swamp wallabies. In SE NSW (Young) (Fig. 4), 12 transects

comprising 155 km of survey effort were flown across the high density stratum. On these

transects, 512 eastern grey kangaroos were counted along with 12 wallaroos, one red-necked

wallaby and 17 swamp wallabies. Eleven transects comprising 139 km of survey effort were

flown across the medium density stratum. On these transects, 78 eastern grey kangaroos

were counted along with one swamp wallaby.

21

Table 4. The total number of sightings of macropods and the raw counts of eastern grey kangaroos (EGK), common wallaroos (CW), red-necked wallabies (RNW) and swamp wallabies (SW) for each of the transects surveyed within the three regions surveyed. The transect lengths given are the actual rather than nominal lengths and each transect is identified in relation to survey stratum by the second letter of its identification code (H = high, M = medium).

Transect

Length (km)

No. of sightings

Raw counts EGK CW RNW SW

Hunter-Mudgee

MH01 10.0 14 69 - - - MH02 10.0 4 16 - - - MH03 4.7 2 3 1 - - MH04 10.0 1 2 - - - MH05 10.0 1 2 - - - MH06 10.0 12 33 - - 1 MH07 10.0 3 10 - - - MH08 10.0 21 45 - - - MH09 10.0 - - - - - MH10 10.0 4 14 - 1 - MH11 10.0 5 7 1 - 1 MH12 6.6 - - - - - MH13 7.6 22 100 - - - MH14 10.0 26 93 - - - MH16 4.3 3 5 - 1 - MH17 8.8 5 3 2 2 - HM02 12.0 2 3 1 - - HM03 12.0 8 25 - - - HM04 5.6 6 21 - - - HM05 12.0 8 19 1 - - HM06 12.0 23 59 5 1 - HM07 6.7 2 5 - - - HM08 6.8 3 7 - - - HM09 12.0 11 28 2 - - HM10 12.0 3 1 1 - 1 HM11 5.1 4 11 - - - HM12 12.0 7 12 - - - HM13 12.0 3 9 - - - HM14 7.4 6 16 5 - - MM01 10.0 4 7 - - - MM02 10.0 5 5 - - - MM03 5.8 1 5 - - - MM04 10.0 1 1 - - - MM05 10.0 - - - - - MM06 10.0 4 14 1 - - MM07 10.0 3 7 - - -

22

MM08 10.0 12 37 3 - 1 MM09 10.0 1 1 - - - MM10 10.0 2 7 - - - MM11 7.6 1 5 - - - MM12 7.9 2 7 - - - MM13 6.3 8 19 1 - - MM14 10.0 4 48 - - - MM15 5.8 2 13 - - - MM16 10.0 1 4 - - - Central Tablelands CH02 15.0 22 84 2 - - CH03 15.0 19 46 2 - - CH04 15.0 6 21 - - 1 CH05 15.0 10 50 - - - CH06 15.0 31 83 5 - - CH07 8.3 7 29 - - - CH08 15.0 10 31 - - - CH09 5.6 2 7 - - - CH10 10.0 18 66 - - 1 CH11 15.0 12 36 - - - CH12 15.0 12 38 1 2 - CH13 14.0 47 168 - - 1 CH14 4.1 - - - - - CH15 9.5 13 20 - - 3 CH16 14.9 34 85 7 - - CH17 9.3 10 24 - - 3 CH18 3.6 - - - - - CH19 14.1 11 30 1 - 8 CH20 15.0 15 27 - - 2 CH21 10.0 7 6 1 - - CH22 15.0 14 40 - - - CM01 15.0 - - - - - CM02 15.0 - - - - - CM03 11.3 5 22 - - - CM04 15.0 2 4 - - - CM06 10.1 12 19 - 1 1 CM07 15.0 4 8 - - - CM08 8.9 12 127 - - 2 CM09 14.8 11 29 - 2 1 CM10 15.0 1 - - - 1 CM11 15.0 29 89 3 1 1 CM12 15.0 - - - - -

CM14 15.0 2 6 - - - CM15 15.0 3 14 - - - CM16 15.0 33 153 1 - -

23

SE NSW(Young) YH01 15.0 18 46 - - 2 YH02 13.3 5 1 2 1 1 YH03 15.0 14 58 - - - YH04 15.0 47 119 - - 2 YH05 15.0 20 37 2 - 6 YH06 15.0 9 27 - - 1 YH07 15.0 8 6 1 - 2 YH08 15.0 21 62 1 - - YH09 12.4 14 73 3 - - YH10 9.4 2 11 - - - YH11 5.2 9 41 3 - 3 YH12 9.7 9 31 - - - YM01 15.0 - - - - - YM02 9.4 - - - - - YM03 15.0 - - - - - YM04 13.8 3 6 - - - YM05 15.0 9 28 - - - YM06 9.7 1 1 - - - YM07 15.0 4 29 - - - YM08 14.1 - - - - - YM09 15.0 3 4 - - 1 YM10 11.2 3 6 - - - YM11 6.2 3 4 - - -

 

Population and density estimates were determined for eastern grey kangaroos only.

With only 27 sightings of clusters of common wallaroos, nine sightings of red-necked

wallabies and 24 sightings of swamp wallabies across all three proposed management zones

(Table 4), there was insufficient data to determine reliable population and density estimates

for these three species.

In determining population estimates for each of the proposed new management zones,

where possible, the data were analysed separately for the high and medium density strata

and the results combined to produce whole-zone population and density estimates. This was

able to be done for all three proposed zones, although in the case of the proposed SE NSW

(Young) zone, the survey results (Table 4) had to be combined across the high and medium

strata in order to fit a global detection function that could then be used to determine the

density of eastern grey kangaroos in the medium density stratum. There were enough

24 sightings to allow the results for the high density stratum of this proposed zone to be analysed

separately.

Densities in the low density strata of each of the proposed new management zones

were assumed to be equivalent to zero. For the high and medium density strata, analyses

were first conducted with the within-stratum survey results pooled and then with these data

post-stratified on the basis of observer and side-of-aircraft. Post-stratification was only used

when the number of observations within each of the levels of post-stratification were >40.

With this being the case, post-stratification was used in analysing the survey results for the

high density strata of the proposed Hunter-Mudgee zone, the high and medium density strata

of the proposed Central Tablelands zone and the high density stratum of the proposed SE

NSW (Young) zone. Limited sample sizes precluded post-stratification from being used in the

remaining strata (see n in Table 5).

The results of the analyses for eastern grey kangaroos are given in Table 5. In each

stratum of each proposed new zone, the strategy for modelling the detection function that

produced the lowest AIC value was that of first modelling the combined data for a stratum

without any form of post-stratification, and then applying separately the two post-stratification

options.

The detection functions were of the form of a Uniform, Half-normal or a Hazard-rate key

function. Where an adjustment was made to the key function to improve the fit to the survey

results, it was with a Cosine adjustment term (Table 5). The forms of the detection functions

derived using data from each of the two strata within each of the three proposed management

zones are shown in Figs. A1.1-A1.7 of the Appendix 1. The values of Pa, the probability that

a randomly placed cluster of eastern grey kangaroos within the covered region of the survey

strip (here, a survey strip 150 m wide) would be detected (Buckland et al. 2001), showed little

variation (<10%) within the proposed Hunter-Mudgee zone. Contrary to this, greater variation

between side-of-aircraft and observer (<32%) was observed in the proposed Central

Tablelands zone, and to some extent between side-of-aircraft (<16%) in the proposed SE

NSW (Young) zone (Table 5).

The densities of eastern grey kangaroos within the two strata of each of the three

proposed kangaroo management zone are given in Table 5. In the proposed Hunter-Mudgee

25

Table 5. Results of the helicopter line transect surveys of eastern grey kangaroos conducted in the prospective Hunter-Mudgee, Central Tablelands and SE NSW (Young) KMZs in September, 2008. Given along with the areas of the strata surveyed within each zone, are survey effort, the number of clusters of kangaroos sighted (n), the detection function models, the probability that a cluster of is detected if it is in the covered region (Pa) and the estimated density (±1SE) of eastern grey kangaroos for each stratum along with its associated coefficient of variation (CV%). Where post-stratification has been used in the analysis, it has either been by survey aspect (N = north, S = south) or observer (DB and SS).

Kangaroo management zone Area (km2) Effort (km) n Model Pa Density (km-2) CV (%)

Hunter-Mudgee

High 10,274 142.0 61 50

Uniform/Cosine (N) Hazard-rate (S)

0.32 0.28

22.30 ± 6.57 29.4

Medium 7,646 143.4 44 Half-normal 0.27 7.38 ± 2.14 29.0

Hunter medium 7,406 127.5 74 Half-normal/Cosine 0.29 19.92 ± 4.67 22.4

Central Tablelands

High 8,254 253.4 42 59

Half-normal (N) Half-normal (S)

0.37 0.49

20.76 ± 2.95 14.2

Medium 14,378 195.1 121155

Half-normal (DB) Hazard-rate (SS)

0.41 0.26

25.33 ± 8.07 31.9

SE NSW (Young)

High 3,185 155.0 78 67

Half-normal/Cosine (N) Half-normal/Cosine (S)

0.38 0.27

26.29 ± 5.65 21.5

Medium 3,353 139.4 26 Half-normal/Cosine 0.33 4.76 ± 1.67 35.0

26

zone, densities were essentially the same within the high density stratum and the Hunter-

medium stratum (z = 0.29, P = 0.77; Buckland et al. 2001, p. 85). Both these densities were

significantly higher than the density in the medium density stratum (medium versus high:

z = 2.15, P = 0.03; medium versus Hunter-medium: z = 2.44, P = 0.01). These results provide

some support for the stratification that was used in design of the survey conducted in this

proposed zone (Fig. 2). The Hunter-medium was included as a separate stratum because it

was thought that with relatively small landholding probably making up most of its area,

eastern grey kangaroo densities would perhaps be lower than in the high density stratum.

Although this appears not to be the case, it does not negate the stratification used.

Stratification is an effective tool ensuring good coverage in designing a survey. In the

proposed Central Tablelands zone, no difference was found between the densities of eastern

grey kangaroos in the designated high and medium density strata (z = 0.53, P = 0.60).

Although stratifying a large area as part of a survey design is always a worthwhile exercise, in

this instance, now that information is available in the form of transect line counts of kangaroos

(Table 4), the opportunity exists to reconsider the stratification used in the present survey

design (Fig. 3). In the proposed SE NSW (Young), a difference was found between the

densities of eastern grey kangaroos in the designated high and medium density strata

(z = 3.65, P << 0001). This result provides some support for the stratification that was used in

the design of the survey conducted in this proposed zone (Fig. 4).

The whole-zone population estimates for eastern grey kangaroos in the three proposed

new management zones are given in Table 6. These estimates have been determined by

summing the population estimates for the two strata of each zone surveyed. The standard

errors given with these estimates were derived from pooling the variances for the strata.

Given also with these estimates is a combined estimate for the total population of eastern

grey kangaroos in the survey area that lays between the existing Upper Hunter and South

East NSW zones (Fig. 1). The surveys of the three proposed new zones were designed with

the intention of producing population estimates of eastern grey kangaroos with coefficients of

variation of around 20%. This was essentially achieved.

Whole-zone densities for eastern grey kangaroos were derived from the population

estimates in Table 6 and are given in Table 7. These were determined in relation to the three

types of survey strata in each proposed zone, i.e. the low, the medium and the high density

27 strata. The low density stratum of each zone was assumed to support zero to negligible

numbers of eastern grey kangaroos.

Both the proposed Hunter-Mudgee and Central Tablelands management zones are

larger than the three Northern Tablelands management zones, but each is comparable in size

to the current South East NSW management zone (Fig. 1). Both support larger, higher

density populations of eastern grey kangaroos than do the three Northern Tablelands

management zones (see Table 9, Cairns 2007). Eastern grey kangaroo density in the

proposed Hunter-Mudgee zone is twice that in the Upper Hunter management zone

immediately to its north. The proposed Central Tablelands zone supports the largest eastern

grey kangaroo population of all survey areas/management zones based on the Great Dividing

Range and its western slopes. It is some 60% higher in density than the population in the

proposed Hunter-Mudgee zone and some 65% higher than the population in the South East

NSW management zone. This might warrant this proposed new management zone being

managed separately rather than in combination with the proposed Hunter-Mudgee zone. The

proposed SE NSW (Young) zone, which will likely be combined with the existing SE NSW

management zone to form an expanded zone supports an eastern grey kangaroo population

comparable in density to those supported in the adjacent Yass and Gundagai RLPB districts

of the existing SE NSW zone (see Table 6, Cairns 2007b).

In a submission made to NSW DECC on behalf of the NSW Farmer’s Association and

the Dubbo, Hunter, Forbes, Central Tablelands, Molong and Young RLPBs requesting the

area comprising these RLPB districts be opened up for commercial kangaroo harvesting

(Mulligan 2007), figures were provided on the number of non-commercial (121) culling

licences issued during the period 2000-2007. In two of these RLPB districts, namely Forbes

and Molong, very few licences have been issued, with the result being that only a small

number of eastern grey kangaroos having been culled from these districts during the period

2002-2007; about 620 per district per year. Only negligible numbers have been culled from

the Dubbo and Young districts. Contrary to this, however, an average of 11,000 eastern grey

kangaroos, along a much smaller number of wallaroos, has been culled from the Central

Tablelands RLPB district each year. In the Hunter RLPB district, an average of 5,600 eastern

28 Table 6. Estimated total numbers (N ± 1SE) of eastern grey kangaroos in the three prospective KMZs, based upon the helicopter line transect surveys conducted in September, 2008. Given also are the coefficients of variation (CV %) for these estimates.

Kangaroo management zone Area (km2) N (± 1SE) CV (%)

Hunter-Mudgee 29,379 433,030 ± 77,533 17.9

Central Tablelands 23,105 535,600 ± 118,607 22.1

SE NSW (Young) 8,884 99,698 ± 18,841 18.9

Hunter-Mudgee/Central Tablelands combined

52,484 968,630 ± 141,700 14.6

Table 7. Estimated densities (±1SE) of eastern grey kangaroos in the three prospective KMZS based upon the helicopter line transect surveys conducted in September, 2008. These densities have been derived in relation all strata (high, medium and low density) comprising each management zone.

Kangaroo management zone Area (km2) Eastern grey kangaroos (km-2)

Hunter-Mudgee 29,379 14.74 ± 2.64

Central Tablelands 23,105 23.18 ± 5.13

SE NSW (Young) 8,884 11.22 ± 2.12

Hunter-Mudgee/Central Tablelands combined

52,484 18.46 ± 2.70

grey kangaroos, along a much smaller number of wallaroos, have been culled annually, while

in the Mudgee-Merriwa district, an average of some 22,000 eastern grey kangaroos have

been culled each year. Harvest quotas set at 15% will exceed these numbers given the

estimated sizes of the eastern grey kangaroo populations in the proposed new Hunter-

Mudgee and Central Tablelands management zones (Table 6) and should lead to a

substantial fall in the number of animals culled non-commercially. This has occurred in the

South East NSW management zone which was first opened for commercial harvesting in

2004 (N. Payne, pers. comm.).

29 6. Acknowledgements

As with any project, the job is never completed without the support of others who are either

wittingly or unwittingly drawn in to provide assistance. For his invaluable GIS support, Greg

Lollback has been included as a co-author of this report, as has David Bearup who put in

considerable effort each evening in helping the pilot plan the next day’s surveys. Paul Caristo

provided excellent and obliging service as the pilot. His attention to OH&S issues was well

appreciated. Scott Seymour obliged by acting as one of the observers during the course of

the survey. As well as beginning his training as an observer, Mike Saunders contributed

valuable logistical support during the survey.

7. References

.Anon. (2006). New South Wales Commercial Kangaroo Management Plan 2007-2011.

Department of Environment and Conservation. 63 pp.

Borchers, D.L & Burnham, K. P. (2004). General formulation for distance sampling. In:

Advanced Distance Sampling (eds. S. T. Buckland, D. A. Anderson, K. P. Burnham, J. L.

Laake and L. Thomas). Pp. 6-30.

Buckland, S. T., Anderson, D. A., Burnham, K. P., Laake, J. L., Borchers, D. L. and Thomas,

L. (2001). Introduction to Distance Sampling: estimating abundance of biological populations.

Oxford University Press, Oxford.

Cairns, S. C. (2003). A report to the New South Wales National Parks & Wildlife Service on

the consultancy: Kangaroo Monitoring New England Tablelands Helicopter Survey.

Unpublished report to New South Wales National Parks & Wildlife Service, Dubbo, NSW.

18 pp.

Cairns, S. C. (2004a). A report to the New South Wales Department of Environment and

Conservation on the consultancy: Kangaroo Monitoring – Redesign and Analysis of the

Northern Tablelands Region Helicopter Survey. Unpublished report to New South Wales

National Parks and Wildlife Service, Dubbo, NSW. 45 pp.

30 Cairns, S. C. (2004b). A report to the New South Wales National Parks & Wildlife Service on

the consultancy: Kangaroo Monitoring – South East New South Wales Helicopter Survey.

Unpublished report to New South Wales National Parks and Wildlife Service, Dubbo, NSW.

19 pp.

Cairns, S. C. (2007a). A report to the New South Wales Department of Environment and

Climate Change on the consultancy: ‘Kangaroo Monitoring – Design and Analysis of the

Northern Tablelands Region Helicopter Survey’. Unpublished report to New South Wales

National Parks and Wildlife Service, Dubbo, NSW. 40 pp.

Cairns, S. C. ( 2007b). A report to the New South Wales Department of Environment and

Climate Change on the consultancy: Kangaroo Monitoring – South East New South Wales

Helicopter Survey. Unpublished report to New South Wales Department of Environment and

Climate Change, Dubbo, NSW. 30 pp.

Cairns, S. C., Lollback, G. W. & Payne, N. (2008). Design of aerial surveys for population

estimation and management of macropods in the Northern Tablelands of New South Wales,

Australia. Wildlife Research 35: 331-339.

Clancy, T. F. (1999). Choice of survey platforms and technique for broad-scale monitoring of

kangaroo populations. Australian Zoologist 31: 367-274.

Clancy, T. F., Pople, A. R. & Gibson, L. A. (1997). Comparison of helicopter line transects

with walked line transects for estimating densities of kangaroos. Wildlife Research 24: 397-

409.

Hill, G. J. E. (1981a) Distribution of grey kangaroos in south, inland Queensland. Australian

Rangeland Journal 3: 58-66.

Hill, G. J. E. (1981b) A study of the habitat preferences in the grey kangaroo. Australian

Wildlife Research 8: 245-254.

Mulligan, A. (2007). Application for New Kangaroo Commercial Zone. Mudgee-Merriwa Rural

Lands Protection Board. 10 pp.

New South Wales National Parks & Wildlife Service. (2001). The New South Wales

Kangaroo Management Program. A management program for the utilisation of four kangaroo

species in NSW. (New South Wales National Parks and Wildlife Service: Sydney) http://www.nationalparks.nsw.goc.au/npws.nsf/Contents/Kangaroo+management+program

31 Payne, N. (2007). Population Monitoring Methods for the NSW Kangaroo Management

Program. Department of Environment and Conservation, NSW. 17 pp.

Pople, A. R. ( 2003). Harvest Management of Kangaroos during Drought. Unpublished

report to New South Wales National Parks & Wildlife Service, Dubbo, NSW. 27 pp.

Pople, A. R. (2008). Frequency and precision of aerial surveys for kangaroo management.

Wildlife Research 35: 340-348.

Pople, A. R. & Grigg, G. C. (1998). Commercial harvesting of kangaroos in Australia.

Environment Australia, Canberra. http://www.ea.gov.au/biodiversity/trade-use/wild-

harvest/kangaroo/harvesting/index.html

Pople, A. R., Cairns, S. C. & Menke, N. (2003). Monitoring Kangaroo Populations in

Southeastern New South Wales. Unpublished report to New South Wales National Parks &

Wildlife Service, Dubbo, NSW. 24 pp.

Sahukar, R., Gallery, C., Smart, J. & Mitchell, P. (2003). The Bioregions of New South

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Southwell, C. J., & Sheppard, N. (2000). Assessing harvested populations of the euro

(Macropus robustus erubescens) in the Barrier Ranges of western NSW. Australian

Mammalogy 21, 165-171.

Southwell, C. J., Weaver, K. E., Cairns, S. C., Pople, A. R., Gordon, A. N., Sheppard, N. W. &

Broers, R. (1995). Abundance of macropods in north-eastern New South Wales, and the

logistics of broad-scale ground surveys. Wildlife Research 22: 757-766.

Strindberg, S., Buckland, S. T. & Thomas, L. (2004). Design of distance sampling surveys

and Geographic Information Systems. In: Advanced Distance Sampling (eds. S. T. Buckland,

D. A. Anderson, K. P. Burnham, J. L. Laake and L. Thomas). Pp. 190-228.

32 Thomas, L., Laake, J. L., Strindberg, S., Marques, F. F. C., Buckland, S. T., Borchers, D. L.,

Anderson, D. R., Burnham, K. P., Hedley, S. L., Pollard, J. H., Bishop, J. R. B. & Marques, T.

A. (2005). Distance 5.0 Release “x”. Research Unit for Wildlife Population Assessment,

University of St. Andrews, UK. www.ruwpa.st-and.ac.uk/distance/

33

Appendix 1

The detection function models for eastern grey kangaroos (M. giganteus)

in the three proposed new kangaroo management zones.

34  

Fig. A1.1. The Uniform/Cosine (top) and Hazard-rate (bottom) detection functions for eastern grey kangaroos in the high density stratum of the proposed new Hunter-Mudgee KMZ. 

35

Fig. A1.2. The Half-normal detection function for eastern grey kangaroos in the medium density stratum of the proposed new Hunter-Mudgee KMZ.

36

Fig. A1.3. The Half-normal detection function for eastern grey kangaroos in the Hunter-medium stratum of the proposed new Hunter-Mudgee KMZ.

37

Fig. A1.4. The two Half-normal detection functions for eastern grey kangaroos in the high density stratum of the proposed new Central Tablelands KMZ.

38

Fig. A1.5. The Half-normal and Hazard-rate detection functions for eastern grey kangaroos in the medium density stratum of the proposed new Central Tablelands KMZ. DB and SS represent two different observers.

39

Fig. A1.6. The two Half-normal/Cosine detection functions for eastern grey kangaroos in the high density stratum of the proposed new SE NSW (Young) KMZ. 

40

Fig. A1.7. The Half-normal/Cosine detection function for eastern grey kangaroos in the medium density stratum of the proposed new SE NSW (Young) KMZ. 

41

Appendix 2

General performance in terms of detection function models of the four

observers used in the surveys of the three proposed new kangaroo

management zones:

• David Bearup – Hazard-rate

• Scott Seymour – Half-normal

• Stuart Cairns – Half-normal

• Mike Saunders – Half-normal

42  

 

 

43